Analyses of Mitogenome Sequences Revealed that Asian Citrus Psyllids (Diaphorina citri) from California Were Related to Those from Florida

Fengnian Wu,Marylou Polek,Christopher M Wallis,Guangwen Liang,Hongyan Jiang,Luci Kumagai,Zheng Zheng,Jianchi Chen,Yijing Cen,Xiaoling Deng

doi:10.1038/s41598-017-10713-3

Abstract

Asian citrus psyllid (ACP, Diaphorina citri Kuwayama) transmits “Candidatus Liberibacter asiaticus” (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB). CLas has recently been found in California. Understanding ACP population diversity is necessary for HLB regulatory practices aimed at reducing CLas spread. In this study, two circular ACP mitogenome sequences from California (mt-CApsy, ~15,027 bp) and Florida (mt-FLpsy, ~15,012 bp), USA, were acquired. Each mitogenome contained 13 protein coding genes, 2 ribosomal RNA and 22 transfer RNA genes, and a control region varying in sizes. The Californian mt-CApsy was identical to the Floridian mt-FLpsy, but different from the mitogenome (mt-GDpsy) of Guangdong, China, in 50 single nucleotide polymorphisms (SNPs). Further analyses were performed on sequences in cox1 and trnAsn regions with 100 ACPs, SNPs in nad1-nad4-nad5 locus through PCR with 252 ACP samples. All results showed the presence of a Chinese ACP cluster (CAC) and an American ACP cluster (AAC). We proposed that ACP in California was likely not introduced from China based on our current ACP collection but somewhere in America. However, more studies with ACP samples from around the world are needed. ACP mitogenome sequence analyses will facilitate ACP population research.

Highlights

The first description of ACP was from Taiwan in 19082, one of the four regions (Guangdong, Guangxi, Fujian and Taiwan) in southern China known for its long history of HLB3
Taken together the results from analyses of mitogenome sequences (34 ACPs), cox[1] (463 samples), trnAsn (100 samples), and nad1-nad4-nad[5] (252 samples), this study suggested the presence of two distinct clusters: the Chinese ACP cluster (CAC) and the American ACP cluster (AAC)
The Californian ACP was found to group with Floridian ACP, rather than ACP from three provinces in China

Summary

Introduction

The first description of ACP was from Taiwan in 19082, one of the four regions (Guangdong, Guangxi, Fujian and Taiwan) in southern China known for its long history of HLB3. To study the ACP population from different geographical regions, the partial cytochrome oxidase 1 (cox1) gene in the mitogenome of ACP has been used[16,17,18,19,20]. This study attempts to search for the origin(s) of the Californian ACP as well as provide more gene access information of ACP mitogenomes. To this end, the mitogenomes of ACP from California and Florida were sequenced, and compared with a previously reported complete ACP mitogenome from Guangdong, China (mt-GDpsy, NC_030214)[21]. The findings of this study improve current understanding of ACP population diversity and have implications on HLB regulatory practices

Methods

Discussion

Conclusion